The UK has been cleared to begin spot carbon trading again on Friday after the
European Union shut the whole market for two weeks.

Just five countries out of 27, including Britain, were allowed to open their national registries. However, ICE, the main London-based exchange for European trades, will remain closed while other countries improve security.

Under the flagship scheme, companies need permits to emit carbon dioxide as part of the global fight against climate change. Polluters, such as utilities and heavy industry, are granted a certain number of emissions allowances that can be then be traded. However, it has been plagued by allegations of fraud.

More than €70m (£60m) of trade has been disrupted after Europe said it would close the market to spot transactions in mid-January. This followed allegations that 475,000 carbon credits worth €7m were stolen in a hacking attack on the Czech carbon register. Europol estimates carbon trading criminals may have accounted for up to 90pc of all market activity in some European countries in 2009. Fraudulent traders mainly from Britain, France, Spain, Denmark and Holland pocketed an estimated €5bn.

Greg Barker, minister for climate change, said: "It is important to ensure a minimum level of security now to ensure the reopening of the registries. The UK will continue to press the European Commission to ensure that registry security across Europe is raised above this level. This is vital to ensure continued confidence in the market."